Where is the tcltk package?

In view of various bits of advice I've received I tried:

(1) sudo apt-get install r-base r-base-dev

The result:

Reading package lists... Done
Building dependency tree
Reading state information... Done
r-base is already the newest version.
r-base-dev is already the newest version.
The following packages were automatically installed and are no longer 
required:
  linux-headers-2.6.32-28-generic linux-headers-2.6.32-28
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

No improvement in the situation; capabilities("tcltk") still returns FALSE.

(2) re-installing R from source, first doing

     ./configure --with-tcltk

Again no improvement; capabilities("tcltk") still returns FALSE.

WTF?  Why do these things always happen to ***me***? :-)

     cheers,

         Rolf Turner